Currently, aircraft are equipped with various independent embedded systems handling crew-assistance functions. Thus, the current aircraft generally comprise:                a flight management system, known by the acronym FMS, responsible for navigation and, generally, for assisting in management of the flight;        a surveillance system, standalone, of TAWS (Terrain Awareness Warning System) type, or integrated, of ISS (Integrated Surveillance System) type, responsible for a function known as “safety net”, aiming to prevent risk linked to the environment of the aircraft, in particular the risks of collision; a weather radar may be associated with such a surveillance system; thus, a TAWS and a weather radar can be combined within an ISS;        a flight warning system, FWS, responsible for communicating the various warnings to the crew and for displaying the associated procedure(s) when such procedures exist.        
To give more detail, the current flight management systems, FMS, offer the interfaces the crew needs to enter and modify the route that the aeroplane will follow according to its flight plan. These systems are also responsible for the various calculations for optimizing the management of this route with respect to a number of criteria, such as the flight time or fuel consumption. The FMSs do not generate warnings linked to the environment of the craft. Moreover, they do not know the context in which the craft is moving, nor warnings deriving from the other systems of the aircraft. They are therefore not capable of managing the priorities between warnings, nor of presenting to the crew the procedures associated with said warnings.
The surveillance systems, in the form of a standalone computer of TAWS or weather radar type for example, or integrated in an ISS, fulfil a primary surveillance function with respect to the terrain, traffic or weather phenomena in the vicinity of the aircraft, and their role is to issue audible warnings when the operational margins are no longer observed, the objective being to enable the crew to react by, if necessary, undertaking an avoidance manoeuvre.
To handle their function, the surveillance systems, decoupled from the navigation systems, periodically compare the most probable trajectory that the aircraft is expected to follow with:                a cross section of the terrain and with the obstacles being flown over obtained from a world or local digital terrain model embedded on board the computer, with respect to the TAWS;        the situation of weather phenomena situated in the vicinity, with respect to the weather radar.        
In the event of conflict, a spoken message is generally issued and the area originating the warning is presented on a cockpit screen.
However, the surveillance systems are limited: they generate only warnings, and do not present procedures to the crew to assist in resolving the situation that has provoked the warning.
The surveillance systems do not know the context in which the craft is moving, nor warnings deriving from the other systems of the aircraft. Nor, therefore, are they capable of managing priorities between warnings, or of presenting the associated procedures to the crew.
The flight warning systems, FWS, are responsible for managing the warnings issued by the embedded systems. The FWSs centralize the warnings issued and present them to the crew in order of priority. These systems are also responsible for the display of the associated procedures for resolving the warnings raised.
However, the FWSs do not know the trajectory being followed by the aircraft, nor the context in which the craft is moving. They do not know all the warnings deriving from the other systems of the aircraft and are not therefore able to optimally manage the priorities between warnings.
The general problem of the current situation is linked to the fact that the crew of an aircraft moves around in a highly charged cognitive environment. They in fact have to manage the various above-mentioned embedded systems in order to perform all the tasks necessary to the flight and to the guidance of the aircraft. These embedded systems subject the crew to a large number of audible and visual stimuli.
In this context, the known systems have the drawback of not being coupled in order to ensure operational continuity. The consequence of this drawback lies in the fact that inconsistencies may appear, so that unnecessary warnings are raised, or that a future problem is not anticipated.
For example, the integrated surveillance system, ISS, and the flight warning system, FWS, do not know the current flight phase of the aircraft, nor do they generally know its flight plan. The terrain awareness warning system, TAWS, integrated in the ISS, can therefore detect a risk of collision with an obstacle situated straight in front, and raise an associated warning, while the aircraft is located on a trajectory such that it is getting ready for a 90° turn, the warning consequently being unnecessary. Such situations can disturb the crew.
The solutions to these problems, in the state of the art, consist either in deactivating the TAWS-type surveillance system when the aircraft is getting ready to land or take off, or in integrating a flight plan verification function in the TAWS-type surveillance system so that it can inform the crew of the margin that it has with respect to a risk, taking into account the flight plan.
The drawback, in the case of the deactivation of the TAWS, is obvious: the aircraft no longer has an active collision-avoidance surveillance system in the landing or take-off phase. The second case, corresponding to the integration of a flight plan verification function in the surveillance system, does not make it possible to prevent the appearance of unnecessary warnings; it does not handle the management of priorities between warnings, not being connected to the flight warning system FWS.